I 12] 
have off a board or two from a fence at the difiance 
of eight or ten feet from it. In fome parts of the 
country, particularly at Pembroke and Scituate, about 
25 miles S.E. from hence, there were feveral chafms 
or openings made in the earth, from fome of which 
water has iffued, and many cart-loads of a fine 
whitifh fort of fand. Thefe are the principal effedts 
of this earthquake on the land, fome of which argue 
a very quick and violent motion of the earth. Tho’ 
the degree of violence was doubtlefs different in dif- 
ferent places, yet, that I might make fome eftimate 
of it with us, I meafured the greatefl diflance on the 
ground, to which any of the bricks, which were 
thrown off from the tops of my chimnies, had 
reached, and found it to be 30 feet, and the height 
from which they fell was 32 feet. Now fince bodies 
fall thro’ 1 6 feet nearly in*i " of time > and the times, 
in which they fall through other heights, are in the 
fubduplicate ratio of thofe heights ; it follows, that 
the velocity, wherewith thofe bricks were thrown 
off, was that of above 21 feet in i 'of time: for 
the fubduplicate ratio of 32 to 16 is the fame as the 
fimple ratio of 30 to a little more than 21. But 
the velocity was lefs at lefs heights : for the key be- 
fore fpoken of, as thrown from off a fhelf in a 
chamber in my houfe, was not thrown fo far, in pro- 
portion to the height thro’ which it fell, as the bricks 
were from the top of the chimnies ; and in my lower 
rooms nothing was thrown down, but a fmall bell 
in the garret was made to ring by it. Hence it ap- 
pears, that our buildings were rocked with a kind 
of angular motion, like that of a cradle ; the upper 
parts of them moving fwifter, or thro’ greater l'paces 
5 
